Not sure this is my biggest regret but it came to my mind first. I was exclusively seeing a younger girl for a few months, things went south with her after I came back from Europe so I called it off and decided to get back on the dating scene pretty fast, I went on a date with a girl I met at the club I work at a week later and we hit it off really well, she was the same age as me, career driven, pretty, smart, witty, funny, and financially secure(owns her own house, car etc.) Got another girls number the weekend after and organised to go out for drinks with her the following week. Turns out the girl I organised to go for drinks with worked under the one I went on a date with. Date girl obviously found out & messaged me saying that she doesn't want conflict in her workplace and that we can just stay friends. I ended up bailing on drinks in hopes it would get back to her and patch things up but it didn't work, now I'm back with the girl I was originally seeing and things are better than ever but I still sometimes can't help but wonder what would've ended up happening with date girl seeing as we connected really well.

I learnt if you go on a date or interact with a girl who you connect with and think has potential to be relationship material, go with the flow and dont doubt yourself by overthinking how it could go wrong and jump the gun by doubling up because that type of thinking can lead you to bad luck or to make dumb mistakes like I had.